When grown indoors, it is common for a plant like calla lily that prefers full sun outdoors to stretch and become lanky.  It would not be beneficial to cut it back as you may set this plant back quite a bit and potentially prevent good flower formation.

The best thing to do will be to get it into more light and get it outdoors as soon as the threat of frost has passed.  This link can tell you what to expect for the last frost date in Mitchell County: https://yardandgarden.extension.iastate.edu/frost-dates-iowa/frost-and-freeze-dates-iowa-madison-muscatine#mitchell

Until you can get it outside, get it to the brightest window location you can find.  If you have access to a grow light, that would be beneficial.  But since we are at this point, only a few weeks away from the frost-free date, it should be fine in the brightest spot until you can move it outside.

When you do move it outdoors, it will be important to slowly acclimate it to brighter light and warmer temperatures.  Initially, place the plants in a shady, protected site. Then, gradually expose the plants to longer periods of direct sun. Closely watch the plants during this period and bring them indoors if the temperatures are forecasted to drop below freezing or if a strong storm is expected.

Once it is growing in more light the new foliage should stand up better, and grow more vigorously.

Here is some additional information on care for calla lily: https://yardandgarden.extension.iastate.edu/how-to/planting-and-caring-tender-perennials

--Aaron